Squirrels

Introduction

Tree squirrels are rodents with large bushy tails, and are native to Europe, Asia and the Americas. The squirrel common to New Jersey is the Eastern Gray Squirrel.

Identification

Squirrels are divided into three groups: large tree squirrels, pine squirrels, and flying squirrels. Large tree squirrels include fox (Sciurus niger), eastern gray (Sciurus carolinensis), western gray (Sciurus griseus), and tassel-eared (Sciurus aberti) squirrels.

As the name suggests, the eastern gray squirrel has predominantly gray fur but it can also have a reddish color. It has a white underside and a large bushy tail. Black ones are common in some northern parts of their range. Eastern gray squirrels measure 16 to 20 inches. They weigh from 1 1/4 pounds to 1 3/4 pounds.

Habitat
Gray squirrels inhabit both hardwood and coniferous forests.

Food Habits

Gray squirrels will eat a great variety of native foods and adapt quickly to unusual food sources. Typically, they feed on mast (wild tree fruits and nuts) in fall and early winter. Acorns, hickory nuts, walnuts, and osage orange fruits are favorite fall foods. Nuts are often cached for later use. In late winter and early spring they prefer tree buds. In summer they eat fruits, berries, and succulent plant materials. Fungi, corn, and cultivated fruits are taken when available. During population peaks, when food is scarce, these squirrels may chew bark from a variety of trees. They will also eat insects and other animal matter. In urban and suburban areas, they readily eat from garbage cans and bird feeders.

General Biology, Reproduction, and Behavior
Gray squirrels breed when they are 1 year old. They breed in mid-December or early January and again in June. Young squirrels may breed only once in their first year. The gestation period is 42 to 45 days.

During the breeding season, noisy mating chases take place when one or more males pursue a female through the trees.

They nest in tree cavities, human-made squirrel boxes, or in leaf nests. Leaf nests are constructed with a frame of sticks filled with dry leaves and lined with leaves, strips of bark, corn husks, or other materials. Survival of young in cavities is higher than in leaf nests. Cavities are the preferred nest sites.

About 3 young comprise a litter. At birth they are hairless, blind, and their ears are closed. Newborns weigh about 1/2 ounce (14 g) at birth and 3 to 4 ounces (84 to 112 g) at 5 weeks. Young begin to explore outside the nest about the time they are weaned at 10 to 12 weeks. At weaning they are about half of their adult weight.

Home range size depends on the season and availability of food. It may vary from 1 to 100 acres (0.4 to 40 ha). Squirrels move within their range according to availability of food. They often seek mast-bearing forests in fall and favor tender buds in elm and maple forests in the spring.

During fall, squirrels may travel 50 miles (80 km) or more in search of better habitat. Squirrel populations periodically rise and fall. During periods of high populations, squirrels may go on mass emigrations. At such times many animals die.

Squirrels are vulnerable to numerous parasites and diseases. Ticks, mange mites, fleas, and internal parasites are common. Squirrel hunters often notice bot fly larvae (called “wolves” or “warbles”) protruding from the skin. These fly larvae do not impair the quality of the meat for eating.

Squirrels are a food source for hawks, owls, snakes, and several mammalian predators. Predation seems to have little effect on squirrel populations.

Typically about half the squirrels in a population die each year. In the wild, squirrels over 4 years old are rare, while in captivity individuals may live 10 years or more.

Damage and Damage Identification
Squirrels may occasionally damage forest trees by chewing bark from branches and trunks. In residential areas, squirrels sometimes travel powerlines and short out transformers. They gnaw on wires, enter buildings, and build nests in attics. They frequently chew holes through pipelines used in maple syrup production.

Squirrels occasionally damage lawns by burying or searching for and digging up nuts. They will chew bark and clip twigs on ornamental trees or shrubbery planted in yards. Often squirrels take food at feeders intended for birds. Sometimes they chew to enlarge openings of bird houses and then enter to eat nestling songbirds.

In gardens, squirrels may eat planted seeds, mature fruits, or grains such as corn.

Economics of Damage and Control

Squirrels cause economic losses to homeowners, nut growers, and forest managers. The extent of these losses is not well known.

Squirrels caused 177 power outages in Lincoln, Nebraska, in 1980, which was 24% of all outages. Estimated annual costs were $23,364 for repairs, public relations, and lost revenue. In Omaha, in 1985, squirrels caused 332 outages costing at least $47,144. After squirrel guards were installed over pole-mounted transformers in Lincoln in 1985, annual costs were reduced 78% to $5,148.

Legal Status

Squirrels are usually classified as game animals in states where they occur. The tassel-eared squirrel is normally a protected species. Check with local or state authorities to determine legal status of squirrels in your area.

Damage Prevention and Control Methods

Exclusion
Install sheet metal bands on isolated trees to prevent damage to developing nuts. Close external openings to buildings to stop damage to building interiors. Place an 18-inch (46-cm) section of 4-inch (10-cm) diameter plastic pipe or a one-way door over openings to allow squirrels to leave and prevent them from returning. Plastic tubes on wires may prevent access to buildings.

Cultural Methods and Habitat Modification

Remove selected trees or their branches to prevent access to structures.

Repellents
Naphthalene (moth balls), Ro-pel, capsaicin, and polybutenes are registered for controlling tree squirrels.

Toxicants
None are registered.

Fumigants
None are registered.

Trapping
Box and cage traps.

Contact Little Rascals Nuisance Wildlife Removal Services to schedule an inspection!